¹³¹I‐Meta‐iodobenzylguanidine in the Management of Metastatic Midgut Carcinoid Tumors

Abstract

The management of metastatic neuroendocrine tumors incorporates multimodal therapy with surgery, biotherapy, and chemotherapy. Tumor-targeted therapies using radiolabeled octreotide and metaiodobenzylguanidine (mIBG) represent a novel treatment approach. The aim of this study was to evaluate the effectiveness of 131I-mIBG in the treatment of metastatic midgut carcinoid tumors. survival outcomes were assessed for patients treated at two regional cancer centers and then compared. One center used 131I-mIBG routinely in the management of metastatic carcinoid tumors (center A), and the other did not use this modality (center B). Only patients with histologically proven metastatic carcinoid tumor shown, or thought most likely, to be of midgut origin were included in the study. During the period 1980 to 2002, a series of 58 patients from center A with metastatic carcinoid tumor arising from the midgut underwent multimodality therapy with the addition of 131I-mIBG. Their median age was 64 years. The median dose of 131I-mIBG administered was 6751 MBq, and there was an average of 2.8 treatments per patient. During the same period, 58 patients with metastatic carcinoid were treated at center B with similar multimodality therapy without the use of 131I-mIBG therapy. Their median age was 65 years. Survivals at 3 and 5 years were 77% and 63%, respectively (95% CI 47-75), for group A. The 3- and 5-year survivals for group B were 56% and 47% (95% CI 34-59), respectively. The mean follow-up was 6.6 years for group A and 5.0 years for group B. Although retrospective in nature, this study suggests that the addition of 131I-mIBG therapy to the treatment protocol of patients with metastatic midgut carcinoid tumors prolongs survival.

Assessment of the efficacy and toxicity of 131I-metaiodobenzylguanidine therapy for metastatic neuroendocrine tumours

“…The proportion of patients experiencing symptomatic benefit from 131 I-MIBG therapy (56.3%) was similar to that reported in previous studies (Safford et al, 2004;Sywak et al, 2004). As in one previous similar study (Safford et al, 2004), survival after 131 I-MIBG therapy was best predicted by a subjective symptomatic response to treatment.…”

“…It is thought that emission of ionising radiation at this site results in tumour decay (Mukherjee et al, 2001;Rose et al, 2003;Pasieka et al, 2004). This therapy has been used to treat NETs of various types, including gastroenteropancreatic NETs (Pathirana et al, 2001;Pasieka et al, 2004;Safford et al, 2004;Sywak et al, 2004;Buscombe et al, 2005), paraglangliomas (Mukherjee et al, 2001;Safford et al, 2003;Fitzgerald et al, 2006), phaeochromocytomas (Castellani et al, 2000;Rose et al, 2003;Safford et al, 2004;Fitzgerald et al, 2006), medullary carcinoma of the thyroid (Castellani et al, 2000(Castellani et al, , 2003Mukherjee et al, 2001) and neuroblastomas (Howard et al, 2005;Matthay et al, 2007). A number of previous studies had demonstrated significant symptomatic benefit in 40 -60% of patients with metastatic NETs following 131 I-MIBG therapy (Safford et al, 2004;Sywak et al, 2004), in a safe and cost-effective manner (Pathirana et al, 2001).…”

Molecular radiotheranostics for neuroendocrine tumours

“…Interestingly, Sywak et al compared two groups of patients with midgut NETs. 36 The first group (n=58) was treated in a centre where 131 I-MIBG was available while the second group (n=59) had no access to 131 I-MIBG (or other radio-targeted treatments). The 5-year survival rate in the first group was 63% versus 47% in the second group (p=0.1)…”

Long-Term Outcome and Toxicity After Dose-Intensified Treatment with 131I-MIBG for Advanced Metastatic Carcinoid Tumors

“…Such therapy makes use of specific cellular structures, the reuptake mechanism, and storage granules in specialized neuroendocrine cells to target and concentrate within tumor cells (7,8). Since their introduction into routine clinical practice in the 1980s, most reported 131 I-MIBG treatment protocols have comprised therapeutic activities between 3.7 and 11.1 GBq (100 and 300 mCi, respectively) per course (9,10). Some centers use body weight-adapted schedules, such as 92.5 MBq/kg (2.5 mCi/kg) (9,10).…”

“…Since their introduction into routine clinical practice in the 1980s, most reported 131 I-MIBG treatment protocols have comprised therapeutic activities between 3.7 and 11.1 GBq (100 and 300 mCi, respectively) per course (9,10). Some centers use body weight-adapted schedules, such as 92.5 MBq/kg (2.5 mCi/kg) (9,10). In more recently introduced dose-intensified schedules, activities of 14.8-18.5 GBq (400-500 mCi) per treatment course were used; high-dose schedules might incorporate more than 22.2 GBq (600 mCi) supported by potential autologous stem cell rescue (11,12).…”